1. Field of the Invention
The present invention relates to a method of growing a semi-polar nitride single crystal thin film and a method of manufacturing a nitride semiconductor light emitting diode using the same.
2. Description of the Related Art
In general, when a nitride semiconductor light emitting diode is manufactured, most single crystal thin films of nitride such as gallium nitride have the c-plane, i.e. the (0001) plane, and can be grown on a c-plane hexagonal system single crystal substrate (e.g. a sapphire substrate) using metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or hydride vapor phase epitaxy (HVPE).
In this manner, the c-plane nitride single crystal thin film shows polarity because a gallium layer and a nitrogen layer are repeatedly stacked along a c crystal axis. This induces an internal electric field. In this case, the internal electric field inside the light emitting diode is responsible for reduction in the recombination rate of electrons and holes, thereby lowering luminous efficiency of the light emitting diode. Piezoelectric polarization also occurs to decrease a luminous wavelength. Thus, it is difficult to realize the light emitting diode using a long wavelength element.
In order to solve this problem, a semi-polar nitride single crystal thin film must be grown. However, when the c-plane hexagonal system single crystal substrate is used, it is difficult to grow the nitride single crystal thin film into a semi-polar plane. Thus, technology of growing the semi-polar nitride single crystal thin film using a substrate with a non-polar plane is required.
Further, when the semi-polar nitride single crystal thin film is grown, crystal defects occur due to a lattice constant difference between the substrate and the semi-polar nitride single crystal thin film. These crystal defects induce non-radiative recombination in the event of the operation of the light emitting diode, thereby generating much heat. Thus, it is necessary to grow the semi-polar nitride single crystal thin film so as to minimize the crystal defects in order to improve light extraction efficiency.